Meters are 100 times as large as centimeters. So, if we have 800 centimeters, that is the equivalent of 8 meters.
In this scenario, we want to know how many meters is equivalent to 7 centimeters. Since 1 centimeter is 1/100 of 1 meter, we can multiply the amount of centimeters by 1/100 to get the measurement in meters. 7(1/100) will yield 7/100 or .07 meters.
To write this in scientific notation, we take 7 and multiply it by 1/100 or 10^(-2). This is written "7x10^(-2) m".
7 centimeters in scientific notation is just 7x10^0 because it is a single unit. Scientific notation allows us to compare the size of numbers more easily.
For instance 7.12x10^3 is much larger than 7.12x10^(-3) due to the exponents and how many "10s" we are mulitplying our number by.